Typewriting machine



Patented ee. 26, 19222.

s'rarssy tra TN NN .N

ALFRED G. F. KUROWSKI, 0F BROOKLYN, NEW YORK, `.LLSSIGIBTOR lTO UNIDERWOOD TYPEVVRITER COMPANY, 0F NEW' YORK, N. Y., A CORPORATION OF DELAWARE.

TYPEWRITING insomnia Application led March 14, `1921. Serial No. 452,359.

To @ZZ whom t 'may concern: l y

Be it known that l, ALFRED G. F. KURowsm, a citizen of the United States, residing in Brooklyn Borough, in the county ot' i Kings, city and State of New York, have invented certain new and useful 'Improvements in Typewriting Machines, of which the following is a speciiication. y y

The present invention relates to case-shitting mechanism, and is shown 'applied to an Underwood standard portable typewriter ln machines ofy this type,a shift-frame carrying the platen is adapted to be shifted to two raised positions by shift-key levers,

one of which is provided with a Capital linger-key, and the other with a Figure iinger-key. The shift-frame is Connectedto a rock-shaft, to which is fixed an operating arm engageable by the shift-key-levers.

Hitherto, in the type of machine herein clescribed, the point/oil engagementoi' the shiftkey-levers with the operating arm has been a relatively iiXed pivot., so that the leverage at the inger-keys remained unchanged throughout the movement oi? the shift-frame.

The inertia of the key-levers and the various parts to be shifted oflers a perceptible resistance to being pnt. in motion, and this gives the operator a distinct shock, making the action of the key-levers hard andunpleasant. Moreover, after having been once set in 'motion, the key-levers move more easily, and there is nothing to absorb the momentum of the operators finger, as a resuit of which the shift-frame is brought up against the usual vstops with a severe blow..

aThe present invention has for its object the provision oit means whereby the initial inertia oit the part to be moved may be overcome and the momentum of the operators iinger absorbed to a large extent before the shift-frame reaches its limiting, position; 1n this way, an easy, pleasant operation of the shift-keys may be obtained. rlhe means employed comprises the substitution of a 'variable point of pivotal connection between the key-levers and the operating' arm, so that the total leverage applied to raising the frame will constantly vary, the greatest leverage being applied in the beginning to overcome theinertia oli the movable parts, and the leverage gradually diminishing to absorb Jthe momentum of the operators finger the 'frame reaches its limiting position.

Other features and advantages will Vhereinafter appear.

1n the accompanying drawings,

Figure 1 is aside view, vertieallysectioned,` showing an Underwood standard portable machine as modified by. this invention, the shift-frame ,beingk in lowermost position.

Figure 2 is a view similar to F ignre 1, showing the' y Capital key depressed to 65 raise the shift-frame to its rst shifted position] f l Figure 3 is a view similar to Figures'1 and 2, showing the y Figure key depressed to raise the shift-frame to its second shifted position.

Figure 1 is a plan view of one end of the machine, containing the parts shownin Figures 1-3. f

In the machine illustrated,character keys 75 (not shown) are" adapted to throw type-bars -10 upwardly' and rearwardly against the front side lof aplaten 11, which is ournaled in a sheet-metal carriage 12.` `The carriage travels to the let'tr under control ofescapementimechanism `(noty shown), and is provided with roller-bearings and 14, by which it travels on sheet-metal tracks 15 and 16. The tracks 15' and 16 form part oiia shift-frame, which also includes a downwardly-extending member 1"( and forwardlyextending members 18, the latter being provided with pivot-screws 19by which the shaft-.trame is pivoted to upper long links 21, said links being in turn pivoted to the main frame 22 by pivots 23 nearly behind, but somewhat below, the normal position of pivots 19.

For guidingthe shift-frame, there is provided a rock-arm 24 provided with a stubshaft or pin 25, on which rests a yoke 26 of the shift-frame, said arm 24 being fast at its rear end to a transversely-extending shaft 27, which is encircled by a spring y(not shown), so tensioned as to assist in lifting the shift-frame. ln order to raise. the shiftframe symmetrically, an arm 24 is fixed to shaft 27 at eachend of the machine. N

For lifting the shift-frame, there is provided a Capitalfor single,y shift-key 29, and a Figure,ordouble, shift-key 30, tulcrumed on the opposite ends of a short shaft 31, which passes through a standard 32 fixed to the trameoi'fthe typewriter. r.lheshaft isheaded at one endoutside of key 30, `and is held by a nut 2O threaded Von the opposite end thereof, said nut. forming a head outside of key 30. The shift-key 29 is provided with a rearward extension 33, and the shittkey 30 is provided with a rearward eXtensionl.

lThe rearward extensions and 34 are adapted to contact with an arcuate surface 37 forming the end of an operating rockarm 38 iiXed to shaft 27. It will be seen that by ldepressing either key 29 or 30, rearward extension 33 or 34: will raise armBS vto rotate shat't 27. .and hence armsQe, upwardly, Pins 25 on .arms 2d will raise the shift-traine.

By depressing the Capital key 29, ythe shift-frame is lifted until an `inwardlyturned heel l0 thereon strikes a set-screw l1 passing through the turned-over end ot an arm 43, thus enabling they second set of types da to print againstthe platen. By ,depressing key 30, the shift-frameis lifted a greater distance until a turnedover end 50 of the shift-frame, strikes against a set-screw 51 vpassing through 'the turned-over end 52 of a bracket 53 iXed to the frame of the machine. To permit the greater movement .of the shirt-frame when key 30 is depressed, means are provided i'or swinging set-screw il out of the path of the inwardly-turnedheel 4:0. Said means consists in pivoting arms 13 near their lower ends on the machine at 60. The arms d3 form the turned-.up portions of a bail ,61, to which is connected `a spring 62, which normally swingsthe arms 43, so that the set-.screws 41 will be effective to` arrest the shift-frame. The bail 61 has fast thereto an upwardly-extending `bracket 63, having` a rearwardly-extending portion 64: adapted to lie normally cna shelf 65 struck up from extension 34. then key 30 is depressed, extension 84 swings bracket 63 rearwardly, thus lrapidly moving set-screw L11 out of the path of heel 10. The platen is thus raised to the second shifted position, enabling types 45 to print thereon. ,i

To produce an easy movement of .the shift-frame, which will be agreeable to the touch or" the operator, the rearward extensions A33 and 3d terminate Aat their ends in curved or cam-portions 35 and 36said caniportions being adapted to contact with the arcuate surface 37 forming the endet operating arm 38. vIt will be apparent, from the illustrations (see Figures 1, 2 and 3), that when key 29 or 30 is depressed, the cam-portion 35 or 36 will ride on arcuate surface 37, the point of contact moving rearwardly, i. e., the length of the rear arm of the key-lever constantly increasing until the shift-frame reaches its limiting position. Since the length of the forward arm ot each key-lever remains constant, it will be seen. that the ratio oi" the forward arm 'to the rearward arm decreases as thel shift-- 1,411 once gradually diminishing as the effective length of rearward arm increases. Moreover, the point at which the leverage of the key-levers lis applied to the operating arm nieves rearwardly of said arm as the shittrame is raised, `thus decreasing the effective length Vof the operating arm and increasing the resisting `torce of the shiftrame. lt willthus be seen thatl the greatest key-lever .leverage is applied to the greatest eiective length of operating arm at the beginning of a stroke. This arrangement renders it comparatively easy to overcome the inertia of the key-levers, and thus avoids the initial shock to the operatorss linger. lt will be further noted that the leverage at the key-lever decreases as the shift-frame is raised, and thatthe vettective length .of operating arm also decreases simultaneously. The resistance oiered by the frame to ,being lifted increases `correspondingly, and the momentum of the operators linger is tius absorbed to a .large eX- tent before the shift-fame reaches its limiting position, in this manner easingthe shock ot' the frame as it strikesthe limiting stops.

lt will be understood by reference tothe drawing that the curved or cani portions 35 and 36 of theextensions 33 and 34 ot the key-levers increase very considerably in curvature adjacent to their `tip ends, so that, as the shift-traineapproaches the limiting stop d1 under the action ofthe keylever 29 .or the stop 51 under the action ot the l ;e.y-levery BO, the section et the cam portion 35 or 36, respectively, which engages the arcuate .surface 37 or' the rockaim 38,diverges at a much greater degree from the arcuate surface 37 than when the shift-frame is inalower position, Consequently, as the shift-trame approaches one of' its limiting positions, the speed oir moreinent oit the rock-farm 38 and the shift-trame reduced relatively to `the speed olf move-- ment oli' the key-levers. ln other words, in such position ot the shift-trame., an equal movement ot the key-lever produces much less movement ofthe shift-traine than when the shift-frame is in a lower position. This reduction in the yspeed of movement of the shirt-traine lessens the torce of the impact of the fra-me on the stops 41 and 51, and hence reduces the jar and vibration incident to. the impact ot the shift-trame on the stops. l

.By reference to Figure 1 ot the drawing.v it will be noted that in the normal positions of the shiit-key-levers 29 and 30, that is` with the shift-traine down. the surface ot the end portion 35 oit the key-lever 29, which engages the larcuate surface 37 oli the rock-arm 38, is curif'ed rearwardly away lll from the arcuate surface 37 of the rockarm more sharply than is theI corresponding surface of the endportion 36 of the sliift-key-lever 30. By reason of `this construction, the end portion 36 of the keylever 30, upon operationy of the lever, is'

caused to roll rearwardly von the arcuate surface 37 of the rock-arm 38 to a greater i the other end to said frame, a rock-shaft,`

rock-arms at each end of said frame, each of lsaid arms being fixed at one end to said shaft and supporting" said frame at the other, end` to shift said framewhen said shaft is rotated, an additional rock-arm fixed to said shaft and having an arcuate surface lengthwise thereof forming a fulcrum surface, and a shift-key-lever for actuating said additional arm to rotate-'said shaft, one end of said key-lever contacting with said' arcuate surface and liavijing a leverage-changing rolling movement thereon.

2. ln a typewriting machine, in coniloination, a shiftable frame, guide-links each pivoted at one end to said machinel and at the other end to said frame, a rock-shaft, roel;-

ai'ms ateach end of said frame, each of said arms being fixed at one end to said shaft and supporting said frame at the other end to shift said frame when said shaft is rotated, an additionalrocl-arm `fixed to said shaft and having an arcuate surface lengthwise thereof forming,` a fulcrum surface, and a shift-key-lever for actuating said additional arm to rotate said shaft,

one end of said key-lever rcontacting, with' said arms being` -iixed at one end'to said shaft and supporting said frame at the other end to shift said frame when said shaft is rotated, an additional rock-arm fixed to said shaftandhaving an `arcuate surface lengthwise thereof forming afulcruin surface, and a shift-key-lever for actuating said additional arm to'rotate said shaft, said key-lever hei-ng ofthe first classr and having a forward arm and a rearward arm, the end of said rearward arm contacting with said arcuate surface and having; a 'i leverage-changing rolling movement thereonduring` operation of the key-lever.

4. In a typewriting machine, in combination, a frame shiftahle to` either of two po-` sitions, guide-links each pivoted at one end to said machine and at the other end-to said frame, a rock-shaft, rock-arms at each end of said frame, each of said arms being` fixed at one end to'said'shaft and supporting said frame atthe other end to shiftfsaid frame when said shaft is rotated, an additional rock-arm fixed to said shaft and having an arcuate surface extending lengthwise thereof and forming` a fulcrum surface, a shiftkey-lever for engagement with said fulcrum surface to actuate said additional arm `to raise the shift-frame to its first shifted `tion,a frame shiftable to either yofvtwo positions, guide-links each pivoted at one end to said machine'and at the other end to said frame, a rock-shaft, rock-arms at' each end of said frame, each of said arms being fixed n at one end to said shaftand supporting said frame at the other end to shiftA said frame when `said shaft is rotated, an additional rock-arm fixed' to said shaft and having an arcuate surface lengthwise `thereof forming` a fiilcrun'i surface, a shift-irey-lever for actuating said additional arm to raise thel shift-frame to` its first shifted* position, a second shift-key-levei' for actuating said additional arm to raise said frame to its second shifted position, and stops for limitingr the upward movement of said frame each of said positions, said key-levers being of the `first 'class and each having a forward arm'.

and a rearward arm, the ends of said rearward arms contacting with said arcuate sur-y face and having" leverage-changing rolling movements thereon during operation of the key-levers. v

[(5. in atypewriting machine, in combination, a shiftable frame, guide-links each pivoted at one end to said machine and at the other end'to said frame, a rock-shaft, rockarms at each end of said frame, each of said arms being fixed at one end to said shaft and f supporting said frameatthe other end to shift said frame when said shaft is rotated, an radditional rock-arm iXed to said shaft andhaving an arcuate `surface lengthwise thereof forming a fulcrum surface, a4 stop for limiting ythe movement of the shiftable frame, and a shift-lrey-lever` for actuating said additional arm, said lever being of the first class and having a forward :arm land a rearward arm, said .rearward arm being provided with an end portion formed to present a curved surface contacting with said arcuate surface and having a lleveragechanging rolling movement thereon during operation of the lrey-leveigthe curvedsurface of said end portion increasing in curvature towards its tip` and being arranged to bring a section `of increased curvature into contact with the arcuate surface ofthe rockarm as the shiftable frame approaches its limiting position, so as to reduce the speed of movement of the frame as it :approaches thel limiting position and thereby decrease the jar and vibration 'incident upon the impact `of the 'shiftable frame vupon the stop.

7. In a typewriting machine, in combination, a frame shiftable to either of two positions, guide-links each pivoted at one end to said machine .and at therother end `to said frame, a rock-shaft, rock-arms `at each end of said frame, each ofsaid arms being fixed at one end to saidshaft and supporting said frame at the other end'to shift said frame when said shaft is rotated, an additional rock-arm fixed to said shaft and having an arcuate surface lengthwise there-z of forming a fulcrum sur-face, a shift-keylever for actuating said additional arm `to raisethe shift-framev to kits `first shifted position, a second shift-key-lever for actuating said additional arm lto raise said frame to its second shifted position,` and stops for limiting the upward movement of said frame in each of said positions, said key-levers be-l ing of the first c-lass and each having a forward arm and a rearward arm, the ends of said rearward arms being provided with curved end portions contacting with said arcuate surface and having leverage-changing rolling'movements thereon during operation of the key-levers. V

8. In a typewritingmachine, comprising a shiftable frame, in combination, means connected to said frame whereby said frame may be shifted, said means comprising a for-- wardly-extendingoperating arm havingl an arcuate surface lengthwise thereof, and a shift-ley-le-ver for actuating said arm, one end of said lever contacting with said arcuate surface," said point of' contactmoving rearwardly on said surface during Aa stroke of said key-lever to vary `the effective length of said operating arm, so that the effective length of said arm is greatest at the beginning of the stroke Vand gradually diminishes.y

`9. In a typewriting machine, .comprising .a shiftable frame, .sin combination, means connected to said .frame whereby said frame may vbe shifted, 'said means comprising an operating arm having anarcuate `surface lengthwise thereof, and a shift-key-leveryfor actuating said arm, said lever `being ofthe first ola-ss andhaving-a forward arm and a rearward arm, said rearward arm contacting with said operating arm, said point Vof contact moving rearwardly on said surface duringa-stroke of said key-lever to vary the effective length of said operatingv arm, so that vthe effective length of :said voperating arm is greatest at the ,beginning of the keystroke and gradually diminishes.y

10. Ina typewriting. machine, comprising a shiftable frame, in combination, .means connected to said frame whereby said frame may be shifted, said means comprising an operating arm having an arcuate surface lengthwise thereof, and a pluralityofshiftkey-levers for actuating said arm through differentI distances, said arcuate surface extending laterally across the pathzof movement of ,all of the key-levers and said keylevers ,beingoperable in contact with said arc-nate surface, Athe point. of contact between each of the .key-levers and lsaidsurface moving rearwardly on said surface during a stroke of thel lever to vary .the effective length -ofsaid operating arm, so that the effective length of said 4operating arm is greatest atthebeginning of the key-stroke and gradually diminishes.n 'f

1l. In a typewriting machine, comprising a shiftable frame,;in combination, ,meansconnected to said frame whereby said frame may be shifted, said means 4comprising an operating armhaving lan .arcuate surface lengthwise thereof, and a shift-.key-lever for actuating said arm, saidlever being of the first class and having a forward arm and a rearward arm, said rearward arm having a curved end portion contacting with said arcuate surface and .rolling thereon during voperation ofthe hey-.lever to vary the point of contact tocorrespondingly vary the leverage ofsaid key-lever andthe veffective length 0f said operating arm, so .that the leverage of said @key-lever and the effective length of said operating arm are greatest at the beginning of the key-stroke and gradually diminish.

. l2. In a typewriting machine, comprising a yshiftable frame. in combination, -means connected to said 'framelwhereby said frame may be shifted, said means comprising an operating arm anda plurality of shift-keylevers-for actuating said 4armthrough different distances, said arm being formed to present a surface elongated lengthwise of the arm and extending laterally across the path of movement of both ofthe key-levers, and said key-levers being operablein conineens@ tact with said surface andbeing `so constructed and arranged with respect to said surface that the point of contact-between each of the lrey-levers and said surface moves on said surface during a stroke of the lever to vary the effective length of the operating arm, so that the effective length of said operating arm. is greatest at the beginning of the keystroke and gradually diminishes.

13. A typewriter case-shift mechanism comprising a shiftable frame, a rocl-arm connected to the frame, a plurality of keylevers having arms shaped to roll along saidv 145. A typewriter case-shift mechanism comprising a shiftable frame, a rock-arm connected to the frame, and a plurality of key-levers having arms shaped to roll along said rock-arm, said key-levers being dis posed side by side and said rockar1n having "a broadened tread to co-operate with said ALFRED G. it. KURoWsKi.

Witnesses:

EDITH B. LIBBEY, JENNIE P. THORNE. 

